England coach Hope Powell believes the dramatic 2-1 win against New Zealand will lift the pressure on her players against Group B leaders Japan.
A draw or even a narrow defeat in Augsburg on Tuesday will be enough for England to reach the World Cup quarter-finals as group runners-up.
"The fact we have now got our first victory will hopefully allow us to relax a little bit more," said Powell.
Either hosts Germany or France would be their opponents next Saturday.
A victory at the Augsburg Stadium would see England overtake Japan, described as the "Barcelona of women's football", as group leaders.
And Powell is expecting a difficult match against Norio Sasaki's team, fourth in Fifa's world rankings, who are already guaranteed a place in the last eight after beating New Zealand 2-1 before demolishing Mexico 4-0.
"They are a good technical side, they are really good in possession," she told BBC Sport.
"I think we need to try and stifle their strengths, which is keeping the ball, and try to work to our strengths."
England fought back from a goal down to beat New Zealand last Friday, Jill Scott equalising before substitute Jess Clarke grabbed the winner nine minutes from time.
And Powell attributed the early tournament nerves to the expectation following their excellent pre-competition form.
"When we beat New Zealand their goalkeeper [Jenny Bindon] said to me 'you guys just need to relax' and she's absolutely right," she said.
"I think the expectation is now higher than it's ever been. The pressure of trying to get out of this group is quite intense and the players may have felt that.
"After beating USA and Sweden [in recent friendlies] the expectation was you're going to win every single game.
But when points are on the table and getting out of the group or going home is at stake, that is quite hard for players to manage.
"We've never really experienced that before - we've never been a team that everybody expects to win.
Clarke, who did not feature in the 1-1 draw with Mexico, is hoping for her first start in the competition on Tuesday.
Although Powell remained guarded about team selection, she admitted the second-half changes in Dresden, when Karen Carney was also introduced, had played their part.
"We're in a better position than we've ever been in terms of depth, so it's nice to know that you can bring players on that can make a difference," she said.
"It's a really difficult job when you have to leave players out who work desperately hard and all they want to do is play for their country.
"I know all the girls' strengths and their weaknesses, and it's about trying to win football matches and if those changes work it's great.
"I knew that making those changes might help and we were fortunate enough that it paid off against New Zealand."
England are three points clear of third-placed Mexico, and have a much superior goal difference, but Powell said she does not want to rely on the result from the other match in Group B.
"We go into every game trying to win but we recognise a point will get us out of the group but it's no foregone conclusion," Powell added.